212 



down from the overhanging branches, at the same time as the 'root- 

 system of bow-shaped roots, which issue from the base of the 

 main stem, is constantly increasing in breadth by tiie formation of 

 new root bows. 



The development of this increase of land, which is taking 

 place everywhere where the mangroves occur, is proceeding, as 

 is shown above, from the shores, as the mangrove vegetation first 

 extends along these, slowly working itself outwards. Often the 



'V 



■»#j. 



Fig. b. The small salt pond on Sandy Point. St. Groix. (F. B. phot.) 



ncrease of land takes place most vigorously at the mouth of the 

 fiords, as most material has been supplied by the sea, such as 

 sea-weeds and sand, and in consequence of that a tongue is formed 

 from both sides, which gradually shuts off the bay behind from 

 the sea. In this way we get a lagoon, a water-area more or less 

 shut off from the sea, with which it is only connected by a com- 

 paratively narrow opening with shallow water. ') As more ma- 

 terial is gradually deposited this is closed and a lake with brackish 



^) A. S. 0rsted has earlier mentioned this development of the mangrove 

 vegetation (1. c. p. 565) and also Eggers 187S (p. 11 — 14). 



